/PAYMENT GATEWAY

A payment gateway that bends to the business, not the other way around.

A complete, end-to-end payment gateway infrastructure built for a global client, supporting cross-border payments, multiple payment methods, and full merchant control — all within a single, white-label-ready platform.

Payment Gateway case-study cover artwork

/OVERVIEW

BUILT FOR SCALE. CONFIGURED FOR CONTROL.

PAYMENT GATEWAY
PCI DSS
KYC
MULTI-CURRENCY
WHITE LABEL
AWS

A global client needed a payment gateway that could handle cross-border transactions, support a wide range of payment methods, and give merchants meaningful control over their own flows. Off-the-shelf solutions couldn't accommodate the regional complexity, compliance requirements, and customisation depth required. Evolt designed and built the full infrastructure from the ground up.

/THE CHALLENGE

WHAT THE CLIENT NEEDED US TO BUILD.

Cross-border payment infrastructure is only as good as its ability to adapt. Different regions carry different regulatory requirements, risk profiles, preferred payment methods, and currency considerations. The client needed a gateway that could handle all of it without becoming a compliance liability or an operational bottleneck.

The solution had to be flexible enough for merchants to configure their own payment flows, robust enough to process transactions at scale across multiple countries, and secure enough to satisfy PCI DSS requirements throughout.

GOALS

Support card, Apple Pay, Google Pay, PIX, and cryptocurrency payments through a single gateway

Enable full merchant-level customisation of payment flows, fees, and KYC requirements

Build region-aware fee management and risk classification

Deliver separate admin and merchant back offices with role-based access

Achieve PCI DSS compliance with no cardholder data stored

Deploy on AWS with full Infrastructure as Code reproducibility and CI/CD pipelines

/TECH STACK

TECH STACK

Back-end

.NET 9.0

Admin Dashboard

React 19 | TypeScript 5.7 | Vite 6 | Refine 4

Merchant Dashboard

React 19 | TypeScript 5.7 | Vite 6 | Refine 4

Payment Widget

React 18.3 | TypeScript 5.6 | Vite 5.4

Template Service

Node.js 22 | Fastify v5 | react-email

/THE SOLUTION

ONE PLATFORM. EVERY PAYMENT SCENARIO.

Universal payment flexibility

The gateway integrates with any existing system and supports card, Apple Pay, Google Pay, PIX, and cryptocurrency payments. Merchants can define the default payment method per flow using paymentCode. Deposits, withdrawals, refunds, and settlements are all supported natively, with customisable payment expiration timeouts per merchant.

Fee management

A fully customisable fee engine operates per region and per merchant. Fees can be configured independently for transaction attempts, completed transactions, refunds, withdrawals, settlements, and approvals. Any unused fee type defaults to zero.

KYC & Risk segmentation

Three-tier KYC: Level 1 handled internally, Levels 2 and 3 integrated via Sumsub. Limits are adjustable per KYC level. Risk classification covers Low, High, and Ultra-high country categories, with flexible country reassignment and limit reconfiguration. Merchants can skip or shorten KYC for returning users, and returning users benefit from data pre-fill.

Localisation & UX

Supports multiple languages with automatic geolocation-based language detection. Live currency rate feeds from CoinMarketCap and Open Exchange Rates. Light and dark modes available across both admin and merchant dashboards. UI supports column reordering, hiding, and pinning for personalised data views.

Reporting & analytics

Advanced reporting across transactions, deposits, withdrawals, refunds, and reimbursements. Customisable date ranges and merchant-level filtering throughout. Reports can be delivered automatically by email via an AWS-powered template service.

Admin back office

Full role management, visibility across all transaction types, manual and automatic refund and reimbursement triggers (2FA protected), KYC limit configuration, merchant settlement approval, regional settings, currency thresholds, user blocking, and automated onboarding flows.

Merchant back office

Deposit, withdrawal, settlement, and balance tracking in one place. Merchants can request settlements, view their fee structure, and manage user data securely.

Security & Compliance

No cardholder data is stored at any point; tokenisation is handled via PayTech throughout. The platform is fully PCI DSS compliant, with 2FA protection on all sensitive actions. Full audit and activity logging runs through Signoz, with real-time alerts across both sandbox and production environments via Slack.

Infrastructure & Devops

The platform is AWS-hosted with full Infrastructure as Code for complete reproducibility. Apps run in an EKS cluster with CDN-enabled content delivery, DDoS protection, firewalls, and IAM-based access control. CI/CD pipelines include built-in vulnerability scanning and environment-specific deployments. The database runs on PostgreSQL via AWS RDS with multi-AZ deployment, encryption at rest, automated backups, and alerting for abnormal behaviour.